GB2167561A - Sensing system - Google Patents

Abstract

In a sensing system, a plurality of sensors 14 each sense a physical change, e.g. weight, and provide an analogue electrical output, means 24 convert each of the analogue outputs into separate digital signals readable by a computer 25 and the computer scans the digital signals, analyses each signal separately and provides a selected readout. Thus in a school or other laboratory for example, a plurality of measuring or other sensing equipments 10-13 can be connected up to the computer and the output from each read and analysed to provide a selected readout. <IMAGE>

Description

SPECIFICATION Sensing System This invention relates to a sensing system.

According to one aspect of the invention, we provide a sensing system comprising a plurality of sensors each to sense a physical change, each sensor providing an output comprising an analogue electrical signal, means to convert each of the analogue signals into digital signals readable by a computer, means to feed the signals from each of the sensors into the computer, means to analyse each of signals separately and to provide a selected readout from the computer.

Thus, for example, in a school or other laboratory situation, a plurality of pieces of measuring or other sensing equipment can be connected up to the computer and the output from each read by the computer and analysed to provide a selected readout.

The sensors may each sense the same physical change, e.g. weight, or may sense different physical changes, e.g. one sensor may sense weight whilst another senses temperature, and another may sense conductivity for example.

Means to convert the analogue signals into digital signals for computer use may be incorporated into, additional to, or provided as an accessory for the computer. However, each sensor may have its own means to convert the analogue signal into a digital signal of computer readable form.

Arrangements are known to enable an analogue output from weight apparatus to be fed to an analogue to digital converter and hence to a computer. Further, it is known to use a (usually mechanical or electronic) multi-plexer to enable the outputs from a plurality of apparatus to be sequentially read by a computer, to enable a computer to analyse the outputs individually.

In an arrangement in accordance with the invention, preferably the analogue signals of the sensors when converted to digital signals are anlysed sequentially by means included within the computer programming. Thus, for example, the computer may, without any multi-plexer or the like, analyse the signals from a plurality of sensors, and operate on each signal individually and differently, or the same, as required to provide a readout of each of the physical changes sensed by the sensors simultaneously or separately. Thus, for example, where one sensor is a weight sensor and another sensor is a temperature sensor, the computer may provide a graphical readout on a screen or in hard copy, of weight or temperature variations of an article simultaneously or sequentially with a digital indication of the temperature or weight loss or gain of the article as required.

In a preferred embodiment, at least one of said sensors comprises a weighing apparatus, having a strain gauge transducer to provide an outputdepen- dent on the weight placed on a support part thereof, the strain gauge transducer providing an analogue signal, there being inbuilt into the weighing apparatus an amplifier to amplify said analogue signal, and means to feed said signal to said means which convert the amplified analogue signal to a digital signal readable by a computer.

Preferably means are provided to enable the computer to be operated remotely, for example from within the vicinity of the sensors. Such means may comprise a remote keyboard, connected to the computer by a cable, or means such as an infrared receiving and transmitting device, or a radio link, or any other desired remote operating means.

Thus an experimenter may monitor the taking from the sensors, whilst having full control at his remote location, of the operation of the computer.

According to a second aspect of the invention, we provide a computer programmed to receive a plurality of inputs from a corresponding number of remote sensors, each sensor sensing a physically changing parameter, and to analyse each input sequentially and repeatedly at a rate determined by operator variable parameters of the computer programme and to store in a memory information derived from each of the remote sensors for readout, (as herein defined) when required.

By "readout" we mean either a graphical or other display on a screen such as a conventional visual display unit, or any other digital or analogue readout device, a printout on, for example, paper from a printing machine connected to or separate from the computer, or any other manner of presenting the information as analysed by the computer.

In one example, the information derived from each sensor may be displayer when required, separately from or simultaneously with information derived from an or the other sensor, as determined by the computer operator.

Preferably the sensors each provide an analogue signal dependent on the physically changing parameter and analogue to digital converter means are provided between the sensors and the computer to convert the analogue signals into digital signals readable by the computer, the computer being programmed to read and analyse said converted digitgal signals.

The invention will now be described with the aid of the accompanying drawings, in which: Figure 1 is an illustrative representation of a sensing system in accordance with the first aspect of the invention; Figures 2a to 2f are flow diagrams of computer programs for use in programming a computer according to the second aspect of the invention.

Referring to Figure 1, a plurality of sensors 10,11, 12 and 13 each comprise a strain gauge transducer 14 mounted on a support part 15 of the apparatus on which a central plunger 16 bears. The plunger 16 supports a conventional pan 17.

The strain gauge 14 and support part 15 are only shown in weighing apparatus 10, although apparatus 11, 12 and 13 are identical.

The strain gauge transducer 14 is connected to an amplifier denoted at 18 (again only shown for weighing apparatus 10) which amplified the analogue signal produced by the strain gauge transducer 14.

The amplified analogue signal is then fed from the weighing apparatus 10 to an interface shown at 20.

Similarly, amplified analogue signals from each of the strain gauge transducers 14 of the weiging apparatus 11 to 13 are fed to interface 20, preferably via conventional leads which terminate in plugs received in sockets-of the interface 20.

It will be appreciated that the analogue signals produced by strain gauge transducers 14 are usually of very small amplitude and hence the need for amplifiers 18.

An output connector, such as a conventional computer'D' socket, from the interface, enables the signals to be fed from each of the apparatus 10 to 13 via a conventional ribbon-type cable 21 to an analogue-to-digital converter 24 which converts the analogue signals produced by the weighing apparatus 10 to 13, to digital signals which are readable by a computer 25. The digital signals are fed from the converter 24 along a further ribbon-type cable 21 a to the computer 25.

The computer 25 is a conventional microcomputer having a visual display unit 26 and a keyboard 27, with cassette or disc storage capability as required.

In the present case, a remote control unit 30 is provided which is plugged into a user socket of the computer 25 and has a keyboard 31 so that the computer 25 can be controlled remotely of the computer, for example from within the vicinity of the weighing apparatus 10 to 13, which may be some distance from the computer 25.

Alternatively, an infrared receiving and transmitting device may be provided, or a radio link or any other means to enable remote operation of the computer may be provided.

A remote monitoring screen 32 is also provided which may again be located in the vicinity of the weighing apparatus 10to 13.

No multi-plexer is required to enable the computer to analyse all four of the signals received from the weighing apparatus via the analogue-to-digital converter 24, but rather the computer is programmed to scan the inputs from the apparatus 10 to 13 sequentially and repeatedly, and to analyse the signals received to provide information dependent upon the signal received as hereinafter described.

However, if more than four inputs are required, a multi-plexer could be used if it is not desired to change the programming of the computer 25.

In another arrangement, instead of four (or more) identical sensing weighing apparatus, if desired other sensing apparatus may be provided. Further, all or some of the sensing apparatus may sense different physical changes. For example one sensing apparatus may be provided to sense weight, such as apparatus 10 to 13, whilst another sensor may be provided to sense temperature or conductivity or any other changing physical parameter it is desired to monitor.

Preferably though, whatever type of sensor is provided, this has an amplifier, such as amplifier 18 (or voltage reducer), to provide an output analogue signal of a size which when converted to a digital signal by converter 24, will be compatible with the computer 25. However, such amplifier or voltage reducer two bring the signal to a size compatible with the computer 25, may be provided in the analogueto-digital converter 24, or even in the interface 20 as required.

In place of a single converter 24 as described,to convert all of the analogue signals received from each of the sensing apparatus 10 to 13, if desired, each apparatus may be provided with its own analogue-to-digital converter, in which case the output from the interface 20 may be fed directyto the computer 25.

It will be appreciated that the sensing system described is modular in concept. All of the individual modules, i.e. sensor apparatus 10-13, interface 20, analogue to digital converter 24, computer 25, and remote operatinglmonitoring means 30,32, are all unconnected, so that when it is not required to use the system as described, the modules may be used for other purposes.

Referring now to Figures 2a to 2f, flow diagrams of a suite of computer programs which may be used with the computer 25 to enable the computer to read an analyse the four inputs received thereby is illustrated.

Referring firstly to Figure 2a, an initialising programme is shown. Upon operation of a starting means by a user, the computer loads and displays one or more "pictures" which give brief programme details, instructions for use, or any other message or information it is desired to convey to a user. The user is instructed to select an appropriate key to continue, and upon selection of this key a "read" programme, shown in Figure 2b, is loaded.

Referring not to Figure 2b, when the "read" programme is loaded, it is necessary for a userto insertthe number of sensing apparatus (up to a maximum of four) to be used. Of course, in another programme, more or less than four sensing apparatus could be dea It with, or a multi-plexer could be used as described hereinbefore to increase capacity of the present programme.

Assuming that all four weighing apparatus lotto 13 of Figure 1 are used, the user enters "4" and the dimensions to be measured, in the present example weight dimensions such as kilogrammes.

The system then requires calibration. Conveniently, each sensor apparatus 10 to 13 has first a zero, and then a one kilogramme weight placed thereon, and the programme calibrates any further inputs from any sensing apparatus 10 to 13, depending upon these calibration readings.

Next, a user is required to insert a selected time interval and time period, so that readings are taken from each of the sensing apparatus 10 to 13 each given time interval, for example each sixty seconds or each five minutes, as required for a given time period, for example up to one hour.

When a user is ready, he selects an appropriate key to start taking readings, the programme is then arranged to take a reading at the regular time interval selected by the user, for the selected time period.

When it is time to take a reading, a reading it taken from a first sensing apparatus, for example weighing apparatus 11, and from the reading, using the information collected during calibration, the weight or other physical parameter sensed, is calculated.

The weight or other physical parameter is then displayed and/or printed out in hard copy. When it is again time to take a reading, a reading from the second sensing apparatus, e.g. weight sensor 12 is taken, and so on until readings for all the sensing apparatus 11 to 14 have been taken for the entire selected time period.

If desired, the readings from the sensors 10-13 could be taken simultaneously, that is all readings could be taken within one time interval entered by the user as hereinbefore described.

Further, it may be required to take a reading from one sensor, sensor 10 for example, each minute, and for another sensor, e.g. sensor 11, each 3 minutes.

As each individual sensor 10-13 is treated independently, a user may thus insert different selected time intervals for different sensors 10-13 as required.

At the end of the selected time period, the readings thus taken are transferred to a "save" facility associated with a result programme and a results" menu shown in Figure 2c, is displayed.

Referring now to Figure 2c, the results menu is shown, which is initiated by the "read" programme.

A user selects either an appropriate form of display of the results by selecting key 1,2,3 or 4 or opting to collect further readings (key 5) or to finish the programme (key 6).

Assuming that a user selects key 1, a first result programme will run. Referring to Figure 2d, the first result programme loads the readings from the "save" facility of the "read" programme and after calculating suitable scales for a graph, draws a graph of physical parameter/time, for all the readings of the first sensing apparatus over the selected time period. In this example, the graph drawn is a three dimensional depiction of a two-dimensional graph, with time being drawn along the X axis, and the physical parameter, e.g. weight in kilogrammes, along the Y axis.

In an alternative arrangement, for example if a user selects a second results programme (key 2) instead of a three dimensional type graph, an ordinary two dimensional type graph may be displayed. In a still further arrangement, for example if a user selects a third results programme (key 3) a scatter graph may be displayed, and the programme may include a facility to calculate the line of best fit (this step is illustrated in dotted line in Figures 2d) although of course any other manner of depicting the results obtained may be provided (as described below for example).

Referring again to Figure 2d, after the results have been displayed on a suitable graph, a user has the option to print out a copy of the graph on a printer.

Next the user may request a graph of the results for the second sensing apparatus to be displayed and then for the third and fourth sensing apparatus as required. When all the required results have been obtained, a user may return to the results menu and select another key, either to display the results in an alternative way, i.e. different type of graph, orto finish the programme.

Figure 2 e gives an alternative results programme in which a graph is not produced, but rather a list of the results stored in the "save" facility. Again a user has the option of providing a printout on a printer of the results displayed.

Figure 2fshows a "finish" programme which is loaded when an appropriate key (key 6) is selected from the results menu. Another series of pictures displaying instructions or information to a user is then loaded and displayed. If desired, the finish programme may allow for a tune to be played through a suitable transducer to indicate to a user that the programme has ended. Thereafter the screen is cleared and the programme finishes.

Of course, the programme herein before described is only illustrative of the type of programmes which can be used with the apparatus described with reference to Figure 1. Any other desired programme could be run and the results could be displayed in many alternative ways to the graph and list hereinbefore described.

Although as described the results from the individual sensing apparatus 11 to 14 have been displayed sequentially, if desired the results may be displayed simultaneously, either on the same ordinates of a graph, in different columns of a table or in any other manner as required. However, whichever type of programme is used, the programme preferably has the facility to scan a plurality of inputs from a plurality of sensor apparatus and to analyse the results from each of the sensing apparatus independently, thereby obviating the need to provide any multiplexer or the like.

Claims (16)

1. A sensing system comprising a plurality of sensors each to sense a physical change, each sensor providing an output comprising an analogue electrical signal, means to convert each of the analogue signals into digital signals readable by a computer, means to feed the signals from each of the sensors into the computer, means to analyse each of signals separately and to provide a selected readout from the computer.

2. A sensing system according to Claim 1 wherein the sensors each sense the same physical change.

3. A sensing system according to Claim 1 wherein the sensors sense different physical changes.

4. A sensing system according to any one of Claims 1 to 3 wherein the means to convert the analogue signals into digital signals for computer use are incorporated into, additional to, or provided as an accessory for the computer.

5. A sensing system according to any one of Claims 1 to 4wherein each sensor has its own means to convert the analogue signal into a digital signal of computer readable form.

6. A sensing system according to any one of the preceding claims wherein analogue signals of the sensors when converted to digital signals are analysed sequentially by means included within the computer programming.

7. A sensing system according to any one of the preceding claims wherein at least one of said sensors comprises a weighing apparatus, having a strain gauge transducer to provide an output depen dent on the weight placed on a support part thereof, the strain gauge transducer providing an analogue signal.

8. A sensing system according to Claim 7 wherein inbuilt into the weighing apparatus there is an amplifier to amplify said analogue signal, and means to feed said signal to said means which convert the amplified analogue signal to a digital signal readable by a computer.

9. A sensing system according to any one of the preceding claims wherein means are provided to enable the computerto be operated remotely.

10. A sensing system according to Claim 9 wherein the remote operating means comprises a remote keyboard, connected to the computer.

11. A sensing system substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

12. A computer programmed to receive a plurality of inputs from a corresponding number of remote sensors, each sensor sensing a physically changing parameter, and to analyse each input sequentially and repeatedly at a rate determined by operator variable parameters ofthe computer programme and to store in a memory information derived from each of the remote sensors for readout, (as herein described) when required.

13. A computer according to Claim 12 wherein the information derived from each sensor may be displayed when required, separately from or simultaneously with information derived from an orthe other sensor, as determined by the computer operator.

14. A computer according to Claim 12 or Claim 13 wherein the sensors each provide an analogue signal dependent on the physically changing parameter and analogue to digital converter means are provided between the sensors and the computer to convert the analogue signals into digital signals readable by the computer, the computer being programmed to read and anlayse said converted digital signals.

15. A computer when substantially programmed according to the computer programme described hereinbefore and/or shown in Figures 2a to 2f of the accompanying drawings.

16. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.